Reducing wastage and increasing shelf life of root vegetables during washing, packing and retailing


Rotting of potatoes after washing and packing can be a significant cause of consumer complaints, and as a result has economic consequences for the fresh potato supply chain. The pathogens responsible for causing soft rotting are pectolytic bacteria, principally Pectobacterium species. 

This short feasibility study was commissioned to determine if techniques used in other sectors, such as the medical and veterinary industries, could be of value in the potato industry. In particular, the researchers were asked to establish whether the techniques could be used by staff in packhouses to rapidly quantify the numbers of soft rotting bacteria on tubers at intake and/or after washing. Data on the numbers of bacteria present on a sample of tubers and the extent of soft rotting in the same stock were recorded with the aim of developing soft rot risk categories, with high risk stocks being those that are likely to show significant soft rot breakdown problems under commercial conditions.

The project was a HortLINK feasibliity study involving Albert Bartlett, the British Carrot Growers Association (BCGA), Forsite Diagnostics Ltd, Horticulture Development Company, QV Foods, Smiths Detection – Diagnostics and Potato Council


A LAMP assay was designed and characterised for detection of pectolytic soft rotting bacteria (Pectobacterium and Dickeya spp.). Integration of this assay with an LFD DNA extraction method for on-site use was demonstrated. It was shown that LFD extraction can be performed on-site with expedited testing of the LFDs (by LAMP / LATE PCR) at Fera, or the entire LAMP protocol can be performed on-site. Crude and magnetic bead-based extracts were used in conjunction with the Genie II from Optigene for semi-quantitative on-site detection. 

Using the LAMP technique it was possible to relate rotting of potato tubers (under optimum conditions for pathogen multiplication) to the initial numbers of Pectobacterium spp. present on the tubers. Three rotting categories were tested using commercial stocks of potatoes:

  • 0-103 colony forming units (cfu)/tuber (low risk);
  • 103 to 105 cfu/tuber (medium risk);
  • 105 cfu/tuber and above (high risk).

All tested stocks identified as being in the high risk category showed significant soft rot breakdown problems under conducive conditions.

Originally it was anticipated that the short feasibility study would be used as the basis to develop a full HortLink research proposal. This would have provided a route to carry out further development of the diagnostic technologies. However, by the end of the feasibility study, the HortLink funding stream was no longer considering new proposals. Therefore, although it has was possible to demonstrate the potential of packhouse diagnostics, further development work, with the aim of reducing the time required to analyse samples, was not been pursued.

Project code:
01 October 2009 - 30 September 2011
AHDB sector cost:
Total project value:
Project leader:
John Elphinstone


20128 Packhouse Diagnostics LINK R427-1

About this project

To assess the potential to use diagnostics to improve quality control and provide better decision support during washing and packing operations.